After dropping out of the University of Houston in 2004, Mullenweg worked for CNET in San Francisco, with the understanding that he could keep working on his side project ... which became WordPress, the blogging platform that currently supports 16 percent of the internet.

Still only 20 years old, Stacey Ferreira has been working her startup MySocialCloud.com since high school, together with her brother Scott. Last year, she dropped out of NYU when Sir Richard Branson announced he'd be investing in her company.

The story of how she met Branson in the first place is like a case study in a textbook for budding entrepreneurs. Via Twitter, Branson asked people to donate $2000 to charity, for a chance to meet with him over "intimate cocktails." Ferreira and her brother borrowed the money from their parents, went to Miami, and impressed the magnate -- despite the fact that Ferreira wasn't technically old enough to drink at the time of the meeting.

Still only 26 years old, Tumblr founder David Karp not only didn't graduate from college -- he dropped out of high school. The site is now the 9th most-visited on the web, and Karp is a multimillionaire.

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